The present invention relates generally to controllers and, more particularly, to a controller for a passive motion device.
Continuous passive motion (CPM) orthosis devices provide an important rehabilitative treatment used by many doctors and therapists for the treatment of injuries or as part of a postoperative recovery plan. Continuous passive motion devices are typically motor driven and are designed to exercise a particular joint by repeatedly extending and flexing the joint. The devices are capable of applying continuous motion to the joint in a consistent manner and can be adjusted to operate at different speeds and within a defined range of motion affecting the joint.
A continuous passive motion device is typically associated with a controller which determines the parameters by which the device operates. The parameters can include the speed at which the device motor runs, the range of motion, the forces on the patient and any other suitable parameters. Many prior art controllers are only capable of operating a specific type of orthosis device, such as an anatomically correct knee CPM orthosis device.
Thus, there was a need for a universal CPM controller which is compatible with different types of orthosis devices; e.g. hand, toe, non-anatomically correct knee devices based upon a plurality of input parameters relating to a particular orthosis CPM device which are inputted into the universal controller. The parameters relate to the speed at which extension and flexion occur, the angular velocity at which a specified pivot point corresponding to the joint to be exercised is translated, and the force experienced by the joint during the course of motion. The parameters are entered on a keypad by a therapist or the patient. Other parameters that are specific to the particular orthosis CPM device, such as the physical capability of the device, the drive geometry, the motor power to the force relationship, the motor speed to angular velocity, and the type of device are entered in the form of a binary code which is received by the controller and used to retrieve information from a software look-up table to determine the type of CPM orthosis device to be controlled. The controller operates the particular orthosis device according to the specified parameters and is capable of detecting and diagnosing faults which occur during the operation of the device.
A universal CPM controller of this type is taught in Universal Controller for a Continuous Passive Motion Devices filed on Sep. 16, 1991 by Telepko of which this application is a continuation-in-part. The controller taught by Telepko could control a plurality of different types of orthosis devices. This control included control of the speed of the extension and flexion of the orthosis devices. However, the device taught by Telepko, as well as the other known controller devices, merely starting flexing and extending the joints of the user even though movement, especially movement corresponding to the full programmed range, may be painful to the patient.
Therefore, there is a need for a universal CPM controller which is effective to gradually advance the patient to the full range and speed of the program. Additionally, there is a need for a universal CPM controller which is capable of providing tensioning to the joints of the user when immediate flexion and extension are not appropriate.